Gwei

Gwei is the practical, human-scaled unit traders and developers actually see when quoting Ethereum transaction costs. Because a single Wei is far too small to work with (1 ETH equals one billion Gwei, or 10⁹ Wei), the network's gas market is priced and displayed in Gwei instead, much like cents make dollar amounts easier to read than fractions of a dollar.

Every transaction consumes a set amount of gas units (a simple ETH transfer uses 21,000; a smart contract call can use far more), and the total fee equals gas used multiplied by the gas price in Gwei. Since the EIP-1559 upgrade, that price splits into a network-set base fee, which is burned and adjusts automatically with block demand, and an optional priority fee (tip) paid to the validator to speed inclusion. Wallets like MetaMask show both the estimated gas limit and the current Gwei price before a user confirms a transaction.

Gwei values fluctuate with network congestion: fees can spike into double digits during periods of heavy demand, such as popular NFT mints or DeFi activity, and fall to a fraction of a Gwei during quiet periods. Watching the Gwei price is standard practice for anyone timing an Ethereum transaction, since submitting during low-demand windows can meaningfully cut costs, especially for gas-intensive smart contract interactions.